Transverse frame adjustment means for silk screen printing apparatus

ABSTRACT

In silk screen printing machines in which there is a printing frame required to be transversely registered, a pair of longitudinally arranged parallel guides, the printing frame being slidably mounted on said guides for reciprocable movement in a first direction, a second pair of longitudinal guides arranged at right angles to said first pair of guides and coupled to said first pair of guides for reciprocable movement in a second direction at right angle relative to said first direction, the printing frame being mounted to said first and second pair of guides, a first rack and pinion coupling capable of moving said printing frame in said first direction and a second rack and pinion coupling operable on said pair of second guides to move said printing frame in said second direction, a worm gear coupled to the pinion of said second rack and pinion coupling and an endless screw coupled to said worm gear and to said printing frame. A control wheel is operatively coupled to said worm gear by way of said endless screw, manipulation of said wheel being effective to move said printing frame along said second pair of guides to effect movement thereof in the second direction.

United States Patent Brasa 145] Oct. 7, 1975 TRANsvERsE FRAME ADJUSTMENTMEANs FOR SILK SCREEN PRINTING APPARATUS [76] Inventor: Umberto Brasa,Uguccione da Pisa, No. 6, Milan, Italy [22] Filed: June 28, 1973 [21]App]. No.: 374,756

[30] Foreign Application Priority Data Primary Examiner-J. Reed FisherAssistant ExaminerR. E. Suter Attorney, Agent, or Firm-Silverman & Cass,Ltd.

[57] ABSTRACT In silk screen printing machines in which there is aprinting frame required to be transversely registered, a pair oflongitudinally arranged parallel guides, the printing frame beingslidably mounted on said guides for reciprocable movement in a firstdirection, a second pairof longitudinal guides arranged at right anglesto said first pair of guides and coupled to said first pair of guidesfor reciprocable movement in a second direction at right angle relativeto said first direction, the printing frame being mounted to said firstand second pair of guides, a first rack and pinion coupling capable ofmoving said printing frame in said first direction and a second rack andpinion coupling operable on said pair of second guides to move saidprinting frame in said second direction, a worm gear coupled to thepinion of said second rack and pinion coupling and an endless screwcoupled to said worm gear and to said printing frame. A control wheel isoperatively coupled to said worm gear by way of said endless screw,manipulation of said wheel being effective to move said printing framealong said second pair of guides to effect movement thereof in thesecond direction.

2 Claims, 4 Drawing Figures US. Patent Oct. 7,1975

FIG. 1

TRANSVERSE FRAME ADJUSTNIENT lVIEANS FOR SILK SCREEN PRINTING APPARATUSBACKGROUND OF THE INVENTION This invention relates generally to silkscreen printing machines particularly of the type used to applyimpressions on a paper strip or web, and more particularly provides astructure for transversely adjusting the position of the printing frameof said machine during the printing operation to obtainproper'registra'tion.

In silk screen printing machines, it becomes necessary to adjust theprinting frame in the transverse direction before performing theprinting operation. This is made necessary inorder to obtain properregistration. At the present time, available devices do not meet thepresent needs of the serigraphic technique in this field. Accordingly,it is desired by the invention to provide a satisfactory transverseregistration device for these purposes.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of a silk screenprinting machine illustrating the transverse adjustment device accordingto the invention.

FIG. 2 is a partial sectional view of the device illustrated in FIG. 1taken along lines II-II of FIG. 1 and on an enlarged scale.

FIG. 3 is a partial sectional view taken along lines III- III of FIG. 1and on an enlarged scale.

FIG. 4 is a partial sectional view of the device illustrated in FIG. 1taken along lines IV--IV of FIG. 1 and on an enlarged scale.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now to the drawing, inFIG. 1 the printing frame is designated generally by reference character1 and is provided with a pair of lateral gear racks which are notvisible in the Figure but indicated by reference character 2 in FIG. 2.The silk screen printing machine includes stationary portions 22 and 22.The gear racks 2 are operated upon by pinion gears or sprockets 2 sothat the frame 1 is translated or moved reciprocably in the directionindicated by the double-headed arrow A. The pinion gears or sprockets 2are of a width sufficient to enable them to maintain their meshedrelationship with the gear racks 2 when the frame is displacedtransversely in effecting proper registration.

As illustrated in FIG. 1, the printing frame 1 is provided withprojecting parts 3, 4, 5 and 6 exteriorly projecting from the frame.Each part 3, 4, 5 and 6 includes an eye or ring-like support, note FIG.3, suitable to permit passage therethrough of guides 7 and 8 in slidablerelation therewith. The guides 7 and 8 are spatially fixed parallel toeach other longitudinally of the printing frame 1 with the printingframe received therebe tween. Parts 3 and 6 of frame 1 are slidable onguide 7 and parts 4 and 5 of frame 1 are slidable on guide 8.

Each of the guides 7 and 8 terminate in end supports 3, 4', 5' and 6 inwhich there fit, in a right angle direction with respect to the guides 7and 8 themselves, a pair of cross-pieces 9 and 10 respectively. Thedirection of movement of cross-pieces 9 and 10 is indicated bydouble-headed arrows B. Each cross-piece 9 and 10 includes a segmentcarrying gear rack formations 11 and 12 respectively.

The stationary portion 22 of the machine is provided with a pair ofinwardly directed arms 13 and 14 each of which terminate in an eye orring-like support, note FIG. 4, A small shaft 15 is supported in theeyes of arms 13 and 14 and is rotatable, but not transversable in thedirection of double-headed arrows A, and is arranged parallel to thedirection of motion (A) of the printing frame. The shaft 15 carrieskeyed thereupon a pair of pinion gears or sprockets 16 and 17, which arein meshing engagement with the gear racks 11 and 12 respectively.

A helicoidal wheel or worm gear 18 is mounted to shaft 15 on the outsideend thereof, beyond the pinion gear or sprocket 16. The helicoidal wheelor worm gear 18 is in engagement with an endless screw 19, which ismounted vertically on bearing support 20 secured to the frame 1. Theendless screw 19 is rotatable by means of control wheel 21 operable byhand, control wheel 21 forming one piece with said endless screw 19.

Manipulation of wheel 21 causes rotation of the endless screw 19 whichcauses the rotation of the helicoidal wheel 18, which rotates the shaft15 causing movement of the guides 9 and 10 relative to shaft 15 in thetransverse direction, indicated by double-headed arrows B and relativeto the principal longitudinal movement of the frame 1 indicated by thedoubleheaded arrow A. Thus the frame 1 is translated or displacedtransversely toward the right and toward the left, thus registering it,by manipulating the control wheel 21.

Thus in summary, I have described means for effecting transverseregistration of the frame, the frame being provided with lateral gearracks, cooperating with corresponding sprockets for its alternativelongitudinal translation in two opposite directions. The frame isarranged slidably mounted on two longitudinal guides each one of saidguides having their opposite extremities, provided with supports withright-angled or orthogonal axes relative to the axes of said guides. Twocross-pieces are engaged with said supports, each cross-piece beingprovided with a toothed rack segments 1 1 and 12. The machine member 22furthermore is provided with two arms 13, 14 supporting a small shaftwhich is equipped with sprockets or pinion gears 16 and 17 cooperatingrespectively with the toothed segments 11 and 12.

At one end of shaft 15 is keyed a helicoidal wheel 18 which engages anendless screw 19. Screw 19 is arranged with its axis of rotationvertically oriented relative to the axis of rotation of worm gear 18.The screw is braced by the support 20 fastened on the frame. The endlessscrew 19 is rotated by manipulation of control wheel 21 fastened to theend of said screw 19.

What I claim is:

1. In a silk screen printing machine which includes a printing framemovable in a reciprocating operating direction and required to beregistered transversely of said operating direction and first rack andpinion means coupled to said printing frame for effecting reciprocatinglongitudinal translation thereof in said operating direction; said framebeing slidably mounted upon a pair of longitudinal arranged parallelfirst guides, each of said guides having supports at their extremities,said supports having orthogonal axes relative to the first guides,second guides comprising a pair of parallel arranged cross-pieces, eachextending between and engaged with the supports at a common extremity ofsaid first guides along said orthogonal axes respectively, said machinehaving a pair of arms fixed thereto and disposed inwardly of said frameand adjacent to opposite edges thereof and having an elongate shaftsupported between said arms, means to rotate said shaft from a singlelocation therealong, second rack and pinion means coupling each of saidcross-pieces and said shaft at the opposite ends of said shaft to enableboth cross-pieces and the printing frame to be moved in a directiontransverse during operation of the frame in the operating direction toachieve said registration.

2. The apparatus as claimed in claim 1 in which the means to rotate saidshaft comprises a helicoidal wheel secured to said elongate shaft at oneend thereof, an endless screw threadably engaged with the helicoidal ina transverse direction.

1. In a silk screen printing machine which includes a printing framemovable in a reciprocating operating direction and required to beregistered transversely of said operating direction and first rack andpinion means coupled to said printing frame for effecting reciprocatinglongitudinal translation thereof in said operating direction; said framebeing slidably mounted upon a pair of longitudinal arranged parallelfirst guides, each of said guides having supports at their extremities,said supports having orthogonal axes relative to the first guides,second guides comprising a pair of parallel arranged cross-pieces, eachextending between and engaged with the supports at a common extremity ofsaid first guides along said orthogonal axes respectively, said machinehaving a pair of arms fixed thereto and disposed inwardly of said frameand adjacent to opposite edges thereof and having an elongate shaftsupported between said arms, means to rotate said shaft from a singlelocation therealong, second rack and pinion means coupling each of saidcross-pieces and said shaft at the opposite ends of said shaft to enableboth cross-pieces and the printing frame to be moved in a directiontransverse during operation of the frame in the operating direction toachieve said registration.
 2. The apparatus as claimed in claim 1 inwhich the means to rotate said shaft comprises a helicoidal wheelsecured to said elongate shaft at one end thereof, an endless screwthreadably engaged with the helicoidal wheel, support means secured tosaid printing frame and bracing said endless screw so that therotational axis of said screw is vertically oriented and a control wheelis secured to said endless screw coaxial therewith, manipulation of saidcontrol wheel capable of operating said endless screw in turn to rotatesaid helicoidal wheel thereby to rotate the shaft and the pinionsthereby to cause transverse movement of the rack portion of each of thecross-pieces so as to move the frame in a transverse direction.